Reduction of calibration effort in FEM-based optimization via numerical and experimental data fusion

In this paper a fusion metamodeling approach is suggested as a method for reducing the experimental and computational effort generally required for calibrating the parameters of FEM simulations models. The metamodel is used inside an optimization routine for linking data coming from two different sources: simulations and experiments. The method is applied to a real problem: the optimal design of a metal foam filled tube to be used as an anti-intrusion bar in vehicles. The model is hierarchical, in the sense that one set of data (the experiments) is considered to be more reliable and it is labeled as “high-fidelity” and the other set (the simulations) is labeled as “low-fidelity”. In the proposed approach, Gaussian models are used to describe results of computer experiments because they are flexible and they can easily interpolate data coming from deterministic simulations. Since the results of experiments are obviously fully accurate, but aleatory, a second stage (“linkage”) model is used, which adjusts the prediction provided by the first model to more accurately represent the real experimental data. In the paper, the modeling and prediction ability of the method is first demonstrated and explained by means of artificially generated data and then applied to the optimization of foam filled tubular structures. The fusion metamodel yields comparable predictions (and optimal solution) if built over calibrated simulations vs. non-calibrated FEM models.     

Entropy analysis of muscular near-infrared spectroscopy (NIRS) signals during exercise programme of type 2 diabetic patients: Quantitative assessment of muscle metabolic pattern

Diabetes mellitus (DM) is a metabolic disorder that is widely rampant throughout the world population these days. The uncontrolled DM may lead to complications of eye, heart, kidney and nerves. The most common type of diabetes is the type 2 diabetes or insulin-resistant DM.     

A ground-complete axiomatization of stateless bisimilarity over Linda

This paper offers a finite, ground-complete axiomatization of stateless bisimilarity over the tuple-space-based coordination language Linda. As stepping stones towards that result, axiomatizations of stateless bisimilarity over the sequential fragment of Linda without the nask primitive, and over the full sequential sub-language are given. It is also shown that stateless bisimilarity coincides with standard bisimilarity over the sequential fragment of Linda without the nask primitive.     

A defeasible reasoning framework for human mental workload representation and assessment

Human mental workload (MWL) has gained importance in the last few decades as an important design concept. It is a multifaceted complex construct mainly applied in cognitive sciences and has been defined in many different ways. Although measuring MWL has potential advantages in interaction and interface design, its formalisation as an operational and computational construct has not sufficiently been addressed. This research contributes to the body of knowledge by providing an extensible framework built upon defeasible reasoning, and implemented with argumentation theory (AT), in which MWL can be better defined, measured, analysed, explained and applied in different human–computer interactive contexts. User studies have demonstrated how a particular instance of this framework outperformed state-of-the-art subjective MWL assessment techniques in terms of sensitivity, diagnosticity and validity. This in turn encourages further application of defeasible AT for enhancing the representation of MWL and improving the quality of its assessment.     

Interactive Persuasive Systems: A Perspective on Theory and Evaluation

Interactive systems are increasingly used in a growing number of domains to encourage users to perform certain actions or take a certain position toward a given subject. This article offers a perspective on interactive persuasive systems that emphasizes theories and concepts that can guide their design and evaluation. The goal is not to champion a theoretical model over others or to compare the effectiveness of different persuasive strategies but rather to depict the current conceptual landscape in this field and highlight emerging concepts and positions that have recently appeared in it. The article includes a discussion of some representative, general, and domain-specific constructs that can be used to evaluate the effectiveness of interactive persuasive systems.     

Compact half‐mode SIW cavity filters designed by exploiting resonant mode control

This article presents a novel band‐pass filter topology, based on the half‐mode substrate integrated waveguide (HMSIW), which allows for the simple design and easy manufacturing of filters with different bandwidth and number of poles. The design strategy, based on the modification of HMSIW cavity modes, is discussed in the case of two‐pole and four‐pole filters, and two prototypes are implemented and experimentally verified. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:72–79, 2016.     

On the Consequences of the Adoption of the Zaremba–Jaumann Objective Stress Rate in FEM Codes

This paper deals with a particular issue of computational mechanics in main FEM codes nowadays available, i.e. the outcomes of implementations of large strain constitutive models based on the adoption of so-called objective stress rates, in order to satisfy objectivity requirements. The point here is that of directly inquiring whether well-known incoherencies due to the adoption of the Zaremba–Jaumann objective stress rate may manifest themselves when the most used elastic and elastoplastic constitutive models are adopted. The present investigation aims at providing a comprehensive review of the theoretical aspects and at developing an informed knowledge to final users of FEM codes, in terms of exposing which constitutive models and FEM implementations may be affected by Zaremba–Jaumann objective stress rate induced incoherencies. Towards this end, local FEM simple shear tests are explored and clearly show that kinematic cases characterized by a non zero spin may be heavily affected by oscillatory incoherencies, which arise for expected cases, i.e. Cauchy stress responses, but also for other less expected cases, i.e. strain responses, whether they are total, elastic or plastic. Beyond local tests, structural simple shear tests are also performed and show as well that oscillatory incoherencies found in local simple shear tests may heavily influence the overall structural outcomes. A non-secondary target of the paper is that of reviewing the relevant scientific and technical literature about objective stress rates, by critically analyzing correlated issues and proposed solutions, considering scientific contributions spanning over a century, keeping specific attention to the treatment of the Zaremba–Jaumann objective stress rate and to the possible flaws related to its adoption.     

Balancing bike sharing systems with constraint programming

Bike sharing systems need to be properly rebalanced to meet the demand of users and to operate successfully. However, the problem of Balancing Bike Sharing Systems (BBSS) is a demanding task: it requires the design of optimal tours and operating instructions for relocating bikes among stations to maximally comply with the expected future bike demands. In this paper, we tackle the BBSS problem by means of Constraint Programming (CP). First, we introduce two different CP models for the BBSS problem including two custom branching strategies that focus on the most promising routes. Second, we incorporate both models in a Large Neighborhood Search (LNS) approach that is adapted to the respective CP model. Third, we perform an experimental evaluation of our approaches on three different benchmark sets of instances derived from real-world bike sharing systems. We show that our CP models can be easily adapted to the different benchmark problem setups, demonstrating the benefit of using Constraint Programming to address the BBSS problem. Furthermore, in our experimental evaluation, we see that the pure CP (branch & bound) approach outperforms the state-of-the-art MILP on large instances and that the LNS approach is competitive with other existing approaches.     

Towards a new approach to query search engines: the Search Tree visual language

In this paper, we describe theit Search Tree visual language. It is a novel methodology able to support users to build up complex queries to be run on given search engines. For using this visual language, neither parentheses nor precedence rules are needed, nor the specific ability to perform advanced search tasks. The language is proven to have the same expressive power as the expressions in Sum Of Product form. In order to prove the appropriateness of our proposal, we measured the usability of the proposed querying approach against the traditional Yahoo ^TM web search query language. Results show that, even if both the approaches fully support users in terms of efficacy, the Search Tree visual language significantly improves task efficiency, both in terms of the number of actions performed and the time requested with respect to the advanced search interface. Copyright © 2010 John Wiley & Sons, Ltd.     

Agent-oriented software patterns for rapid and affordable robot programming

Robotic systems are often quite complex to develop; they are huge, heavily constrained from the non-functional point of view and they implement challenging algorithms. The lack of integrated methods with reuse approaches leads robotic developers to reinvent the wheel each time a new project starts. This paper proposes to reuse the experience done when building robotic applications, by catching it into design patterns. These represent a general mean for (i) reusing proved solutions increasing the final quality, (ii) communicating the knowledge about a domain and (iii) reducing the development time and effort. Despite of this generality, the proposed repository of patterns is specific for multi-agent robotic systems. These patterns are documented by a set of design diagrams and the corresponding implementing code is obtained through a series of automatic transformations. Some patterns extracted from an existing and freely available repository are presented. The paper also discusses an experimental set-up based on the construction of a complete robotic application obtained by composing some highly reusable patterns.